scholarly journals Isolation of Microbes from Lake Vostok Accretion Ice

2008 ◽  
Vol 74 (15) ◽  
pp. 4962-4965 ◽  
Author(s):  
Tom D'Elia ◽  
Ram Veerapaneni ◽  
Scott O. Rogers
Keyword(s):  
Ice Core ◽  
Rrna Gene ◽  
Microbial Ecosystem ◽  
Lake Vostok ◽  
Cell Concentrations ◽  
Accretion Ice

ABSTRACT Bacteria from seven Lake Vostok accretion and two deep glacial Vostok ice core sections were characterized. The cell concentrations were low, but many of the cells were viable. From the hundreds of cultures, 18 unique bacterial rRNA gene phylotypes were determined. Lake Vostok may contain a complex microbial ecosystem.

scholarly journals Metatranscriptomic and Metagenomic Analysis of Biological Diversity in Subglacial Lake Vostok (Antarctica)

Biology ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 55 ◽  
Author(s):  
Colby Gura ◽  
Scott O. Rogers
Keyword(s):  
Lake Water ◽  
Biological Diversity ◽  
Ice Core ◽  
Biologically Active ◽  
Marine Animal ◽  
Nutrient Sources ◽  
Lake Vostok ◽  
Subglacial Lake ◽  
Basal Ice ◽  
Accretion Ice

A combined metatranscriptomic and metagenomic study of Vostok (Antarctica) ice core sections from glacial, basal, and lake water accretion ice yielded sequences that indicated a wide variety of species and possible conditions at the base of the glacier and in subglacial Lake Vostok. Few organisms were in common among the basal ice and accretion ice samples, suggesting little transmission of viable organisms from the basal ice meltwater into the lake water. Additionally, samples of accretion ice, each of which originated from water in several locations of the shallow embayment, exhibit only small amounts of mixing of species. The western-most portion of the embayment had very low numbers of organisms, likely due to biologically challenging conditions. Increasing numbers of organisms were found progressing from west to east, up to approximately 7 km into the embayment. At that point, the numbers of unique sequences and sequence reads from thermophilic, thermotolerant, psychrophilic, and psychrotolerant organisms increased dramatically, as did sequences from alkaliphilic, alkalitolerant, acidophilic, and acidotolerant sequences. The number of unique and total sequences were positively associated with increases in concentrations of Na+, Ca2+, Mg2+, SO42−, Cl−, total amino acids, and non-purgeable organic carbon. The numbers of unique sequences from organisms reported from soil, sediment, ice, aquatic, marine, animal, and plant (probably pollen) sources also peaked in this region, suggesting that this was the most biologically active region. The confluence of the high numbers of organisms, physiologies, and metabolic capabilities suggests the presence of energy and nutrient sources in the eastern half of the embayment. Data from the main basin suggested a cold oligotrophic environment containing fewer organisms. In addition to bacteria, both the basal ice and accretion ice contained sequences from a diverse assemblage of eukaryotes, as well as from bacteria that are known to be associated with multicellular eukaryotes.

scholarly journals ISOTOPIC REGIME OF SUBGLACIAL LAKE VOSTOK ON EVIDENCE FROM DEEP ICE CORE STUDIES

2015 ◽  
Vol 52 (4) ◽  
pp. 78
Author(s):  
A. A. Ekaykin ◽  
V. Ya. Lipenkov ◽  
A. V. Kozachek
Keyword(s):  
Ice Core ◽  
Lake Vostok ◽  
Subglacial Lake

Chapter 17. Comparative Biological Analyses of Accretion Ice from Subglacial Lake Vostok

2005 ◽  
pp. 251-267 ◽  
Author(s):  
Robin Bell ◽  
Michael Studinger ◽  
Anahita Tikku ◽  
John D. Castello
Keyword(s):  
Lake Vostok ◽  
Subglacial Lake ◽  
Accretion Ice

scholarly journals Reducing the arbitrary: fuzzy detection of microbial ecotones and ecosystems – focus on the pelagic environment

2020 ◽  
Vol 15 (1) ◽  
Author(s):  
Antoine Bagnaro ◽  
Federico Baltar ◽  
Gretchen Brownstein ◽  
William G. Lee ◽  
Sergio E. Morales ◽  
...  
Keyword(s):  
Microbial Communities ◽  
Fuzzy Clustering ◽  
Water Mass ◽  
Rrna Gene ◽  
Microbial Ecosystem ◽  
Transition Zones ◽  
Ecosystem Boundaries ◽  
Operational Taxonomic Units ◽  
Pelagic Environment ◽  
Environmental Transitions

Abstract Background One of the central objectives of microbial ecology is to study the distribution of microbial communities and their association with their environments. Biogeographical studies have partitioned the oceans into provinces and regions, but the identification of their boundaries remains challenging, hindering our ability to study transition zones (i.e. ecotones) and microbial ecosystem heterogeneity. Fuzzy clustering is a promising method to do so, as it creates overlapping sets of clusters. The outputs of these analyses thus appear both structured (into clusters) and gradual (due to the overlaps), which aligns with the inherent continuity of the pelagic environment, and solves the issue of defining ecosystem boundaries. Results We show the suitability of applying fuzzy clustering to address the patchiness of microbial ecosystems, integrating environmental (Sea Surface Temperature, Salinity) and bacterioplankton data (Operational Taxonomic Units (OTUs) based on 16S rRNA gene) collected during six cruises over 1.5 years from the subtropical frontal zone off New Zealand. The technique was able to precisely identify ecological heterogeneity, distinguishing both the patches and the transitions between them. In particular we show that the subtropical front is a distinct, albeit transient, microbial ecosystem. Each water mass harboured a specific microbial community, and the characteristics of their ecotones matched the characteristics of the environmental transitions, highlighting that environmental mixing lead to community mixing. Further explorations into the OTU community compositions revealed that, although only a small proportion of the OTUs explained community variance, their associations with given water mass were consistent through time. Conclusion We demonstrate recurrent associations between microbial communities and dynamic oceanic features. Fuzzy clusters can be applied to any ecosystem (terrestrial, human, marine, etc) to solve uncertainties regarding the position of microbial ecological boundaries and to refine the relation between the distribution of microorganisms and their environment.

scholarly journals Psychromonas boydii sp. nov., a gas-vacuolate, psychrophilic bacterium isolated from an Arctic sea-ice core

2010 ◽  
Vol 60 (1) ◽  
pp. 84-92 ◽  
Author(s):  
Ann J. Auman ◽  
Jennifer L. Breezee ◽  
John J. Gosink ◽  
Peter Schumann ◽  
Carmen R. Barnes ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Sea Ice ◽  
Fatty Acid Content ◽  
Ice Core ◽  
Carbon Sources ◽  
Distinct Species ◽  
Arctic Sea Ice ◽  
Rrna Gene ◽  
Psychrophilic Bacterium ◽  
Phenotypic Analysis

A gas-vacuolate bacterium, strain 174T, was isolated from a sea-ice core collected from Point Barrow, Alaska, USA. Comparative analysis of 16S rRNA gene sequences showed that this bacterium was most closely related to Psychromonas ingrahamii 37T, with a similarity of >99 %. However, strain 174T could be clearly distinguished from closely related species by DNA–DNA hybridization; relatedness values determined by two different methods between strain 174T and P. ingrahamii 37T were 58.4 and 55.7 % and those between strain 174T and Psychromonas antarctica DSM 10704T were 46.1 and 33.1 %, which are well below the 70 % level used to define a distinct species. Phenotypic analysis, including cell size (strain 174T is the largest member of the genus Psychromonas, with rod-shaped cells, 8–18 μm long), further differentiated strain 174T from other members of the genus Psychromonas. Strain 174T could be distinguished from its closest relative, P. ingrahamii, by its utilization of d-mannose and d-xylose as sole carbon sources, its ability to ferment myo-inositol and its inability to use fumarate and glycerol as sole carbon sources. In addition, strain 174T contained gas vacuoles of two distinct morphologies and grew at temperatures ranging from below 0 to 10 °C and its optimal NaCl concentration for growth was 3.5 %. The DNA G+C content was 40 mol%. Whole-cell fatty acid analysis showed that 16 : 1ω7c and 16 : 0 comprised 44.9 and 26.4 % of the total fatty acid content, respectively. The name Psychromonas boydii sp. nov. is proposed for this novel species, with strain 174T (=DSM 17665T =CCM 7498T) as the type strain.

scholarly journals Ice motion over Lake Vostok, Antarctica: constraints on inferences regarding the accreted ice

2000 ◽  
Vol 46 (155) ◽  
pp. 689-694 ◽  
Author(s):  
R. Kwok ◽  
M.J. Siegert ◽  
F. D. Carsey
Keyword(s):  
Ice Core ◽  
Ice Sheet ◽  
Maximum Velocity ◽  
Sar Interferometry ◽  
Surface Velocity ◽  
Parabolic Profile ◽  
Lake Vostok ◽  
The North ◽  
Regional Flow ◽  
Overlapping Data

AbstractIce motion over Lake Vostok, Antarctica, is measured using repeat-pass synthetic-aperture radar (SAR) interferometry. The coverage of the lake and the components of the vector field are resolved using 10 overlapping data takes from ascending and descending look directions. Seventy-day temporal baselines provide the sensitivity required to observe the range of ice motion (0–6 m a−1) over the lake and the adjacent ice sheet. It is remarkable that the scattering field remained coherent over these time separations. This is critical for interferometric analysis and can be attributed to the low surface accumulation and low air temperature at this elevation. The regional flow of the ice sheet around Lake Vostok is from west to east, perpendicular to the surface elevation contours. As the ice flows past the grounding line, a southward component of motion develops that is correlated with the north–south surface slope along the length of the lake. The surface velocity increases slowly from the northern tip of the lake and then more rapidly south of 77° S. At Vostok station, the ice motion is 4.2 m a−1. Across the lake and away from boundary effects, the down-lake flow pattern takes on a parabolic profile with maximum velocity close to the center line of the lake. The overall influence of the subglacial lake is the addition of a down-lake motion component to the prevailing west–east motion of the ice sheet. As a result, we estimate 10% of the mass flowing onto the lake is diverted south. Reconstructions based on the Vostok ice core indicate that the ice was grounded up-glacier from the core site approximately 5000 years ago. This suggests a minimum freezing rate of 40 mm a−1 for the subglacial accretion ice, 10 times greater than that inferred from thermodynamic modeling of the upper 2 km of the ice core.

scholarly journals Antarctic subglacial lake exploration: first results and future plans

2016 ◽  
Vol 374 (2059) ◽  
pp. 20140466 ◽  
Author(s):  
Martin J. Siegert ◽  
John C. Priscu ◽  
Irina A. Alekhina ◽  
Jemma L. Wadham ◽  
W. Berry Lyons
Keyword(s):  
Lake Water ◽  
Ice Core ◽  
Hot Water ◽  
Microbial Life ◽  
Lake Vostok ◽  
Subglacial Lake ◽  
Coastal Margin ◽  
First Results ◽  
Scientific Results ◽  
Subglacial Lakes

After more than a decade of planning, three attempts were made in 2012–2013 to access, measure in situ properties and directly sample subglacial Antarctic lake environments. First, Russian scientists drilled into the top of Lake Vostok, allowing lake water to infiltrate, and freeze within, the lower part of the ice-core borehole, from which further coring would recover a frozen sample of surface lake water. Second, UK engineers tried unsuccessfully to deploy a clean-access hot-water drill, to sample the water column and sediments of subglacial Lake Ellsworth. Third, a US mission successfully drilled cleanly into subglacial Lake Whillans, a shallow hydraulically active lake at the coastal margin of West Antarctica, obtaining samples that would later be used to prove the existence of microbial life and active biogeochemical cycling beneath the ice sheet. This article summarizes the results of these programmes in terms of the scientific results obtained, the operational knowledge gained and the engineering challenges revealed, to collate what is known about Antarctic subglacial environments and how to explore them in future. While results from Lake Whillans testify to subglacial lakes as being viable biological habitats, the engineering challenges to explore deeper more isolated lakes where unique microorganisms and climate records may be found, as exemplified in the Lake Ellsworth and Vostok missions, are considerable. Through international cooperation, and by using equipment and knowledge of the existing subglacial lake exploration programmes, it is possible that such environments could be explored thoroughly, and at numerous sites, in the near future.

First-in-class microbial ecosystem therapeutics 4 (MET4) in metastatic solid cancer patients treated with immunotherapy: MET4-IO.

2020 ◽  
Vol 38 (15_suppl) ◽  
pp. 3098-3098 ◽  
Author(s):  
Daniel Vilarim Araujo ◽  
Marc Oliva Bernal ◽  
Tira Jing Ying Tan ◽  
Alya Abbas Heirali ◽  
Pierre H.H. Schneeberger ◽  
...  
Keyword(s):  
Cancer Patients ◽  
16S Rrna Gene Sequencing ◽  
Intestinal Microbiome ◽  
Rrna Gene ◽  
Solid Cancer ◽  
Fecal Transplant ◽  
Additional Time ◽  
Microbial Ecosystem ◽  
Shannon Diversity ◽  
To Receive

3098 Background: Therapeutic augmentation of the intestinal microbiome to improve immunotherapy outcomes is an active area of investigation. Microbial Ecosystem Therapeutics (METs) are consortia of human-derived bacteria designed to be reproducible, scalable and safe alternatives to fecal transplant. MET4 is a first-in-class consortium of taxa associated with immune checkpoint inhibitor (ICI)-responsiveness. Here we describe preliminary results of MET4-IO, an interventional trial assessing the safety and ecological effects of MET4 in ICI recipients. Methods: MET4-IO is a randomized investigator-initiated trial, evaluating MET4 in solid cancer patients treated with ICI. MET4-IO involves 3 cohorts of 65 total patients: Group A, a safety cohort of 5 patients already on ICI; Group B, patients starting ICI, randomized 3:1 to receive MET4 or not; Group C, patients on ICI who experience radiological progression but not clinical deterioration, randomized 1:1 to receive MET4 or not. Stool and blood samples are collected at baseline and 4-5 additional time-points. For this interim analysis, 16S rRNA gene sequencing was performed on fecal specimens. Shannon diversity, relative abundance (RA), number and fold-change of MET4 taxa > RA 0.01 were assessed and compared to controls. Results: As of January 26, 2020, 21 patients were enrolled (A = 5,B = 12,C = 4), and 15 (71%) received MET4. The mean age was 65.9 years, 40% were females, 52% had head and neck cancer and 19% melanoma. Sixteen patients (76%) were treated with an anti-PD1 agent as monotherapy and 5 with a combination of anti-PD1 and anti-CTLA4 antibodies. G3-4 toxicities (CTCAEv5.0) attributed to ICI were observed in 13% vs. 17% of MET4 exposed and control patients, respectively. Three patients (20%) experienced toxicities attributed to MET4, all grade 1 except G2 dyspepsia in 1 patient. A greater number of MET4-associated taxa were detectable in MET4 recipients than controls (p < 0.01), with a trend towards higher cumulative RA (p = 0.10). No significant change in Shannon diversity after MET4 was observed, however controls were more likely to lose diversity overtime than MET4 recipients (p = 0.05). Colonization with MET4 varied by recipient and by taxon. Bifidobacterium, Collinsella and Enterococcus were significantly more common and abundant in MET4 recipients than controls. Conclusions: In this cohort, MET4 treatment was safe and associated with higher MET4-associated taxa in recipients than controls. Further analyses including peripheral blood immunophenotyping are ongoing. Clinical trial information: NCT03686202 .

Isolation of bacteria and 16S rDNAs from Lake Vostok accretion ice

2001 ◽  
Vol 3 (9) ◽  
pp. 570-577 ◽  
Author(s):  
Brent C. Christner ◽  
Ellen Mosley-Thompson ◽  
Lonnie G. Thompson ◽  
John N. Reeve
Keyword(s):  
Lake Vostok ◽  
Accretion Ice

scholarly journals Community change of microorganisms in the Muztagata and Dunde glacier and climatic and environmental implications

2016 ◽  
Author(s):  
Yong Chen ◽  
Xiang-Kai Li ◽  
Jing Si ◽  
Guang-Jian WU ◽  
Li-De Tian ◽  
...  
Keyword(s):  
Microbial Communities ◽  
Cell Density ◽  
Ice Core ◽  
Ice Cores ◽  
Community Change ◽  
Rrna Gene ◽  
Environmental Implications ◽  
Depth Profiles ◽  
Ice Cap ◽  
Glacier Ice

Abstract. Microorganisms are continuously blown onto the glacier snow, and thus the glacial depth profiles provide excellent geographic archives of the microbial communities. However, it is uncertain about how the microbial communities respond to the climatic and environmental changes over the glacier ice. In the present study, the live microbial density, stable isotopic ratios, 18O/16O in the precipitation, and mineral particle concentrations along the glacial depth profiles were collected from ice cores from the Muztagata glacier and the Dunde ice cap. Six bacterial 16S rRNA gene clone libraries were established from the Dunde ice core. The Muztagata ice core presented seasonal response patterns for both live and total cell density with high cell density occurring in the warming spring and summer. Both ice core data showed a frequent association of dust and microorganisms in the ice. Genera Polaromas sp., Pedobacter sp, Flavobacterium sp., Cryobacteriium sp., and Propionibacterium/Blastococcus sp. frequently appeared at the six tested ice layers, and constituted the dominant species endemic to the Dunde ice cap, whereas some genera such as Rhodoferax sp., Variovorax sp., Sphingobacterium sp., Cyanobacterium sp., Knoellia sp., and Luteolibacter sp. rarely presented in the ice. In conclusion, data present a discrete increase of microbial cell density in the warming seasons and biogeography of the microbial communities associated with the predominance of a few endemic groups in the local glacial regions. This reinforces our hypothesis of dust-borne and post-deposition being the main agents interactively controlling microbial load in the glacier ice.

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